In modern computer systems, a file system stores and organizes computer files to enable a user to efficiently locate and access requested files. File systems may utilize a storage device such as a hard disk drive to provide local access or provide access to data stored on a remote file server. A file system can also be characterized as a set of abstract data types that are implemented for the storage, hierarchical organization, manipulation, navigation, access, and retrieval of data. The file system software is responsible for organizing files and directories.
Typically, to search a file, a file search function is utilized. Given a search term such as a file name, a file extension, or an update time, the file search function can find a file that matches the term from a file system. The file search function is provided in most operating systems and is advantageous in that a flexible search for an objective file can be conducted by changing a search term. However, in a large storage system such as a backup storage system, such a search can consume a long period of time, as the file search function has to search and compare each and entire content file in the storage system. Similarly, antivirus or malware software looking for signatures of target files in the storage system may also consume considerable resources.